Have you installed all the Photoshop updates and MacOS 10.10 updates?
Disabling GPU usage in Photoshop should help with the video driver bugs in MacOS 10.10, until Apple can solve all the driver issues (yes, Apple knows about them and is working on solutions).
What does the long, detailed crash log say?
Also, anything that freezes, shuts down, or reboots the machine is not an application error - but caused by an OS bug, a low level driver bug, or faulty hardware. Applications simply cannot cause those symptoms on modern OSes.
i cannot post te problem report. I don't understand at all. I told you before everthing is up to date
You may not understand the crash report, but we do.
And we need to see the full crash report to know why you are crashing.
I would like to share but I don't know how to share a huge crash report. i tried 2 days without any result. Can you explain how to share a crash report.